The Indian Meteorological Department (IMD) recently released the Aridity Anomaly Outlook (AAO) Index for July 2022, revealing that a whopping 85% of districts across India are facing arid conditions.
Understanding the Aridity Anomaly Outlook Index
The Aridity Anomaly Outlook Index is a tool developed by the IMD to monitor agricultural drought. This kind of drought occurs when rainfall and soil moisture levels are insufficient to support healthy crop growth until maturity, resulting in crop stress. When the index deviates from the normal value, it indicates a water shortage in the affected districts, which could negatively affect agricultural activities.
The AAO Index operates as a real-time drought index wherein the water balance is considered. It calculates the Aridity Index (AI) on a weekly or bi-weekly basis. For each period, the actual aridity is compared with the normal aridity. Negative values suggest a surplus of moisture, while positive values denote moisture stress.
The parameters used by the index include actual and potential evapotranspiration. Actual evapotranspiration refers to the amount of water actually removed from a surface through evaporation and transpiration. Potential evapotranspiration, on the other hand, is the maximum evapotranspiration achievable for a given crop due to evaporation and transpiration.
Applications of the Aridity Anomaly Outlook Index
The index plays a crucial role in understanding the impacts of drought in agriculture, particularly in tropical regions where distinct wet and dry seasons form part of the climate regime. It is applicable to both winter and summer cropping seasons.
Key Findings of the Index
The AAO Index found that only 63 out of the 756 districts in India are non-arid, while the remaining 660 districts face various degrees of aridity. A total of 196 districts are grappling with a ‘severe’ degree of dryness, with Uttar Pradesh topping the list with 65 such districts. Bihar follows closely with 33 districts. Other districts with ‘severe arid’ conditions include parts of Jharkhand, Haryana, Madhya Pradesh, Delhi, Telangana, Maharashtra, Andhra Pradesh, Jammu and Kashmir, Punjab, West Bengal, Rajasthan, Karnataka, and Tamil Nadu. These arid conditions have negatively affected the ongoing kharif sowing, evidenced by a decrease of 13.26 million hectares in the area sown under different kharif crops compared to the same period in 2021.
About the Standardised Precipitation Index (SPI)
The SPI is extensively used to characterize meteorological drought across various timescales. It reflects soil moisture at short timescales and can be correlated with groundwater and reservoir storage at longer timescales. The index highlighted a persisting rainfall deficit in the past six months in areas like UP, Jharkhand, Bihar, West Bengal, and some parts of North East India, hinting at an extreme drought situation that could impact their agricultural activities.
Know More About the Indian Meteorological Department (IMD)
The IMD, established in 1875, is a branch of the Ministry of Earth Sciences. It serves as the primary agency for meteorological observations, weather forecasting, and seismology.
Drought-Prone Area Programme
The Drought-Prone Area Programme aims to minimize the adverse effects of drought on crop and livestock production and the productivity of land, water, and human resources. The ultimate goal is drought proofing of the affected areas. The programme falls under the purview of the Department of Land Resources, Ministry of Rural Development.
Desert Development Programme
The Desert Development Programme intends to reduce the negative impact of drought and control desertification by rejuvenating the natural resource base of identified desert areas. This programme also comes under the Department of Land Resources, Ministry of Rural Development.
National Watershed Development Programme
The National Watershed Development Programme for Rainfed Areas (NWDPRA) is a scheme aimed at the conservation, development, and sustainable management of natural resources. It also aims to enhance agricultural productivity and production in a sustainable manner. The Department of Agricultural Cooperation and Farmer Welfare manages this programme under the Ministry of Agriculture and Farmers’ Welfare.